Earth abundant colloidal carbon quantum dots for luminescent solar concentrators

Luminescent solar concentrators (LSCs) can serve as large-area sunlight collectors, suitable for applications in low-cost optoelectronic devices. The external optical efficiency of LSCs is significantly dependent on the optical properties of the chosen fluorophores. Compared to organic dyes/polymers and inorganic nanocrystals, carbon quantum dots (C-dots) have emerged as a new class of fluorophores in LSCs due to their tunable absorption spectrum, high quantum yield, non-toxicity, environmental friendliness, low-cost and eco-friendly synthetic methods. Major discoveries have been made in this field very recently, while there is a lack of an up-to-date systematic review to summarize the employment of C-dots in LSCs. In this review, we summarized the most recent advances in this field, focusing on the structure-dependent optical properties of C-dots for LSCs. We review various synthetic strategies developed for the synthesis of high-quality C-dots using green precursors and solvents, yielding C-dots with a wide absorption spectrum, large Stokes shift and high quantum yield. We further discuss in detail the relationship between the structure and optical properties of C-dots. We conclude with a detailed account of the latest examples of C-dot applications in the structure and performance of LSCs and give our own perspectives on the remaining key issues and emerging possibilities in the field.